Nanosensor detects toxins in cells

CHICAGO - US scientists have developed a tiny sensor that can detect small amounts of cancer-causing toxins or trace the effectiveness of cancer drugs inside living cells.

The finding, reported yesterday in the journal Nature Nanotechnology, offers a new tool for tracking specific chemicals in the body.

"We made a very small nanosensor that can detect cancer-causing molecules or important therapeutic drugs inside of a single living cell," said Michael Strano of the Massachusetts Institute of Technology, who worked on the study.

"It's much smaller than a living cell in your body," Strano said in a telephone interview. "It's so small it can be placed into environments that aren't accessible with larger sensors."

Strano said the sensors are made up of thin carbon filaments known as carbon nanotubes. His team wrapped carefully shaped tubes with DNA, which offers a binding site for DNA-damaging agents inside cells. The sensors give off a fluorescent light, which changes when they interact with cellular DNA.